A wireless power transmission or a wireless energy transfer refers to a technology of wirelessly transferring electric energy to desired devices. In the 1800's, an electric motor or a transformer employing the principle of electromagnetic induction has been used and thereafter attempts have been performed to transmit electrical energy by irradiating electromagnetic waves, such as radio waves or lasers. Actually, electrical toothbrushes or electrical razors, which are frequently used in daily life, are charged based on the principle of electromagnetic induction. The electromagnetic induction refers to a phenomenon in which a voltage is induced so that a current flows when a magnetic field is varied around a conductor. Although the electromagnetic induction technology has been rapidly commercialized while focusing on small-size devices, the power transmission distance thereof is short.
Until now, the long-distance transmission using the electromagnetic induction, the resonance and the short-wavelength radio frequency have been used as the wireless energy transfer scheme.
However, a typical antenna assembly embedded in a terminal has a thin thickness and the manufacturing process of the antennal assembly is complicated.